On Fri, 08 Aug 2003 18:25:41 -0400, Tom Lane <[EMAIL PROTECTED]>
wrote:
> Two examples: [...]
One more example:
X Y
A A
a B
A C
b A
B B
b C
C A
c B
C C
Correlation for column X is something less than 1.0, OTOH correlation
for an index on upper(X) is 1.0.
>I don't really see
>a way to do this without actually examining the multi-column ordering
>relationship during ANALYZE.
So did we reach consensus to add a TODO item?
* Compute index correlation on CREATE INDEX and ANALYZE,
use it for index scan cost estimation
Servus
Manfred
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